High developing voltage supply apparatus

Abstract

A high developing voltage supply apparatus includes solenoid power switches, and a high developing voltage driver selectively outputting a solenoid driving signal to close one of the solenoid power switches to electrically close a corresponding mechanical contact, applying a high developing voltage to one of color development rollers corresponding to the mechanical contact closed and Kased on an image to be printed. A high developing voltage supply supplies the high developing voltage to developing roll shafts of the other color development rollers to stabilize potentials of the developing roll shafts, or, in the alternative, the high developing voltage supply apparatus may include a voltage supply supplying a self-biased voltage to the other color development rollers using the high developing voltage formed with a DC voltage V DC and an AC voltage V AC superimposed.

1. A high developing voltage supply apparatus, comprising:
 a high developing voltage supply supplying a high developing voltage to developing roll shafts of developers in order for toner to move from a plurality of fixed color development rollers to an OPC drum; 
 a high developing voltage driver for selectively outputting a high voltage driving signal based on an image to be printed in order for the high developing voltage to be selectively applied to the fixed color development rollers; 
 developer power switches to selectively switch the high developing voltage to a select fixed color development roller, of the plurality of fixed color development rollers, in response to the high voltage driving signal; and 
 a voltage divider dividing and supplying the high developing voltage, as selectively switched-to the select fixed color development roller, to remaining fixed color development rollers, of the plurality of fixed color development rollers except the select fixed color development roller, to bias the remaining fixed color development rollers through voltage dividing of the high development voltage provided to the select fixed color development roller, 
 wherein the high developing voltage comprises a DC voltage and an AC voltage superimposed. 
 
   
   
     2. The high developing voltage supply apparatus as claimed in  claim 1  wherein the voltage divider provides a negative voltage when the toner is an electrically negative toner and provides a positive voltage when the toner is an electrically positive toner. 
   
   
     3. The high developing voltage supply apparatus as claimed in  claim 2 , wherein the voltage divider divides the high developing voltage with the resistors inter-connected between the select fixed color development roller and the remaining other fixed color development rollers. 
   
   
     4. The high developing voltage supply apparatus as claimed in  claim 3 , wherein values of the resistors are determined based on an impedance formed by a capacitance due to a gap between the OPC drum and each of the fixed color development rollers and capacitance due to the OPC drum. 
   
   
     5. A high developing voltage supply apparatus, comprising:
 solenoid power switches; 
 a high developing voltage driver selectively outputting a solenoid driving signal to close one of the solenoid power switches to electrically close a corresponding mechanical contact, applying a high developing voltage to a select color development roller, of a plurality of color development rollers, corresponding to the mechanical contact closed and based on an image to be printed; and 
 a voltage divider to divide the high developing voltage supplied to the select color development roller and apply the divided high developing voltage to developing roll shafts of remaining color development rollers, of the plurality of color development rollers except the select color development roller, to bias and stabilize potentials of the developing roll shafts of the remaining color development rollers, 
 wherein when an electrically negative toner is used, a DC voltage of negative level is included in the high developing voltage, and, when a positive toner is used, a DC voltage of positive level is included in the high developing voltage. 
 
   
   
     6. A high developing voltage supply apparatus, comprising:
 solenoid power switches; 
 a high developing voltage driver selectively outputting a solenoid driving signal to close one of the solenoid power switches to electrically close a corresponding mechanical contact, applying a high developing voltage to a select color development rollers, of a plurality of color development rollers, corresponding to the mechanical contact closed and based on an image to be printed; and 
 a voltage divider to divide the high developing voltage supplied to the select color development roller and apply the divided -the high developing voltage to developing roll shafts of remaining color development rollers, of the plurality of color development rollers except the select color development roller, to bias and stabilize potentials of the developing roll shafts of the remaining color development rollers, 
 wherein the high developing voltage applied to a developing roll shafts of the select color development roller, a high developing voltage formed of an AC voltage and a DC voltage superimposed to transfer toner from the select color development roller& to an OPC drum. 
 
   
   
     7. A high developing voltage supply apparatus, comprising:
 solenoid power switches; 
 a high developing voltage driver selectively outputting a solenoid driving signal to close one of the solenoid power switches to electrically close a corresponding mechanical contact, applying a high developing voltage to a select color development rollers, of a plurality of color development rollers, corresponding to the mechanical contact closed and based on an image to be printed; and a voltage divider to divide the high developing voltage supplied to the select color development roller and apply the divided the high developing voltage to developing roll shafts of remaining color development rollers, of the plurality of color development rollers except the select color development roller, to bias and stabilize potentials of the developing roll shafts of the remaining color development rollers, 
 wherein the solenoid power switches selectively close and open mechanical contacts corresponding to the solenoid driving signal output from the high developing voltage driver to selectively transmit the high developing voltage to a developing roll shaft of the select color development rollers. 
 
   
   
     8. The high developing voltage supply apparatus as claimed in  claim 6 , wherein a developing vector between a surface of the OPC drum and the remaining development rollers decreases, so that the toner developed on the OPC drum by the select development roller does not move towards the remaining development rollers.